总结

tokudb_lock_timeout_debug = 0: No lock timeouts or lock deadlocks are reported.
tokudb_lock_timeout_debug = 1: A JSON document that describes the lock conflict is stored in the tokudb_last_lock_timeout session variable
tokudb_lock_timeout_debug = 2: A JSON document that describes the lock conflict is printed to the MySQL error log.
tokudb_lock_timeout_debug = 3: A JSON document that describes the lock conflict is stored in the tokudb_last_lock_timeout session variable and is printed to the MySQL error log.